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Cuprous oxide (Cu2O) nanoplates are synthesised using the Co-precipitation method. The prepared nanoplates is confirmed by using XRD and optical properties was determined by UV-Vis DRS and the direct bandgap was done using Tauc's plot. The band gap values determined for Cu2O nanoplates around 1.69 eV, which is clearly on the visible region. The using TEM image determined the morphology of the prepared Cu2O nanoplates, the observed result was plate like shape. The photocatalytic degradation of Methylene Blue was carried out in visible light. The adsorption was carried out in the dark for 30 min before photodegradation. The MB degradation efficiency for Control and Cu2O nanoplates were 5.1 and 70%, respectively. The MB Degradation efficiency for Cu2O nanoplates for the 13.7 times better degradation rate than without catalyst. [ABSTRACT FROM AUTHOR]

We report herein the analysis of the properties of copper(I) oxide thin films deposited by an optimized ammonium-free successive ion layer adsorption and reaction (SILAR) technique. The Cu2O thin film deposition process was carried out at room temperature using copper acetate monohydrate, sodium citrate as complexing agent, and hydrogen peroxide as precursors of copper and oxygen ions, respectively. The harmless and easy-to-handle sodium citrate replaces the volatile NH4OH commonly employed as complexing agent in the SILAR technique for the deposition of metal oxide thin films. The optical, structural, morphological, and electrical properties of the as-deposited Cu2O thin films were studied as a function of the number of cycles during deposition, as well as their modifications produced by the effect of rapid thermal annealing (RTA) in vacuum in a temperature range of 200–250°C for 1 min, 3 min, and 5 min. The as-deposited thin films had cubic crystalline structure corresponding to the Cu2O phase as determined by x-ray diffraction (XRD), with a direct energy bandgap of 2.43–2.51 eV depending on the number of cycles, and electrical resistivity of the order of 103 Ω cm. The XRD and x-ray photoelectron spectroscopy (XPS) analysis of the Cu2O thin films treated by RTA demonstrated an increase of the crystal size with time and temperature of the RTA and reduction effects from Cu2+ to Cu1+ oxidation states. On the other hand, the RTA treatments also decreased their energy bandgap to 2.38 eV and electrical resistivity to 102 Ω cm. The high energy bandgap values of the Cu2O thin films were attributed to quantum confinement effects produced by their small crystal size in the range of 3.6–8.6 nm. [ABSTRACT FROM AUTHOR]

In this study, we employed the one-dimensional solar cell capacitance simulator (SCAPS-1D) software to optimize the performance of Pb-based and Sn-based (Pb-free) all-inorganic perovskites (AIPs) and organic–inorganic perovskites (OIPs) in perovskite solar cell (PSC) structures. Due to the higher stability of AIPs, the performance of PSCs incorporating Cs-based perovskites was compared with that of FA-based perovskites, which are more stable than their MA-based counterparts. The impact of AIPs such as CsPbCl3, CsPbBr3, CsPbI3, CsSnCl3, CsSnBr3, and CsSnI3, as well as including FAPbCl3, FAPbBr3, FAPbI3, FASnCl3, FASnBr3, and FASnI3, was investigated. SnO2 and Cu2O were selected as an inorganic electron transport layer (ETL) and a hole transport layer (HTL), respectively. CsSnBr₃, CsSnI₃, FASnCl₃, and FASnBr₃ exhibited higher efficiency compared to their Pb-based counterparts. Additionally, most Cs-based perovskites, excluding CsPbI₃, demonstrated better performance relative to their FA counterparts. CsSnI3 AIP device also shows the highest short circuit current density (JSC) of 32.85 mA/cm2, the best power conversion efficiency (PCE) of 16.00%, and the least recombination at the SnO2/CsSnI3 interface. The thickness, doping, and total defect density of CsSnI3 PSC have been systematically investigated and optimized to obtain the PCE of 17.36%. These findings highlight the potential of CsSnI3 PSCs as efficient and environmentally friendly PSCs. [ABSTRACT FROM AUTHOR]

The efficient utilization of visible light catalysts for organic reactions necessitates not only the effective separation of photogenerated electrons and holes to participate in the reaction, but also their ability to form key intermediates with reactant molecules. The present study successfully synthesized a crusiform-like mesoporous structure of nitrogen-doped carbon-coated Cu2O/Cu (Cu2O/Cu/N-C) with a Cu2O/dual electron acceptor interface using etched HKUST-1 as the precursor. A series of theoretical and experimental studies have demonstrated that the Cu2O/Cu/N-C interface in the photocatalytic homo-coupling of terminal alkynes not only effectively enhances the separation of photogenerated electron–hole pairs, but also facilitates the formation of the key intermediate [Cu2O/Cu/N-C]-phenylacetylide and promotes the rearrangement of its internal charges. As a result, the homo-coupling reaction can be effectively facilitated. The primary reason for the functional role of Cu2O/Cu/N-C interface lies in the downward bending of energy band from Cu2O to N-doped C layers, induced by the different work functions of Cu2O, Cu and N-doped C layers. Consequently, Cu2O/Cu/N-C photocatalysts demonstrate exceptional photocatalytic activity in the homo-coupling reaction of terminal alkynes under blue-light irradiation and air atmosphere. The present study presents a novel research methodology for the development of highly efficient visible light catalysts to facilitate organic reactions in future applications. [ABSTRACT FROM AUTHOR]

Semiconducting Cu2O have excellent optical and electronic properties and are more promising candidates for advanced electronic applications. In the current study, pure and 3.125%, 6.25%, and 12.5% Zn doped Cu2O compositions were studied using density functional theory in the framework of wien2k-code. Experimentally, uniform and smooth thin films of these compositions were successfully synthesized through the spin coating technique. The elemental composition and morphology were studied using energy-dispersive X-ray spectroscopy and field emission scanning electron microscopy, respectively. Crystallographic analysis of thin films shows a cubic phase structure having space-group 224 Pn-3m. The total density of states confirms the overlapping of states at the Fermi level for Zn-doped compositions. The significant variations in thermoelectric parameters observed with change of temperature for pure and Zn substituted Cu2O compositions, especially the Seebeck-coefficient values vary from 2.5 × 10−4 to 5.5 × 10−5 VK−1 for these cuprous oxide compositions. The optical-parameter such as absorption and extinction coefficient curves reached maxima at the highest photon energies. The enhancement in transmittance power and reduction in the band gap energy from 2.08 eV to 1.75 eV with the substitution of Zn material enhanced the availability of these compositions for advanced applications. Highlights: DFT calculations of Zn substituted Cu2O compositions. Phase pure growth of uniform and smooth thin films. Cubic phase detected having space-group 224 Pn-3m. A significant variation was observed in thermoelectric and optical properties. Band gap was reduced from 2.08 eV to 1.75 eV with substitution of Zn. [ABSTRACT FROM AUTHOR]

In this study, copper oxide nanoparticles have been produced utilizing a high-purity copper target and a conventional laser system with two separate pulsed laser wavelengths (1064 and 532 nm), which have not been explored in previous works. Physical properties of these wavelengths have been studied. Measurements were made of the particle size, shape, and size distributions. XRD (X-ray diffraction) analyses indicated that the nanofilms were deposited at 1064 nm and are cubic structures with discrimination along the (110) direction. Transmission electron microscopy (TEM) was used to examine nanoparticles with sizes ranging from 76 to 57.5 nm. UV spectroscopy was utilized to determine the optical characteristics of the colloidal solution. The material seems to have a modest UV-VIS spectrum. The flour peak is around 590 nm, which indicates the formation of Cu2O nanoparticles. The indirect bandgap (2.36–2.2 eV), respectively, exhibits a pronounced red shift. These nanoparticles are most likely the result of quantum confinement processes at nanoscales. [ABSTRACT FROM AUTHOR]

In this study, using high-purity copper targets, copper oxide nanoparticles have been obtained using a traditional laser system with low laser fluence, which has not been considered in other works. Physical properties of these fluences have been studied. The current study shows the construction and analysis of Cu2O NPs and characterizes their performance. Nd:YAG laser ablation in DW at various fluences (6.3–8.91–11.46–14.01–16.56) J/cm2 was used to construct the Cu2O layer at a laser wavelength of 1064 nm. Cu2O nanoparticles (NPs) were studied using transmission electron microscopy (TEM), which revealed that their semi-spherical morphologies and average particle size ranged from (63–55) nm, depending on the laser fluences. All of the samples of Cu2O NPs that were analyzed by XRD had a Cube crystal structure, as expected. Measurements of UV–VIS and photoluminescence showed that raising the laser energy caused the absorption and emission wavelengths of Cu2O NPs to shift to red. Cu2O NPs' optical energy gap was varied from (2–1.97) eV in response to changes in laser fluence. [ABSTRACT FROM AUTHOR]

The production of hydrogen fuel using photoelectrochemical water splitting method requires semiconductor materials with suitable energy gap, electrical and optical properties. Cuprous oxide is feasible candidate fulfilling many of these requirements to be the photocathode of such devices. In this study, we investigated optical and microstructural properties of cuprous oxide prepared under different temperatures. Microstructure properties were evaluated by statistical, fractal and Fourier methods. Roughness characteristics, Fourier transforms and multifractal characteristics provide consistent information connected with the distribution of surface objects created during sample fabrication. Our methodology is feasible to provide practical insights for the fabrication and monitoring of surface and optical properties of Cu2O and other semiconductor materials. [ABSTRACT FROM AUTHOR]

To develop persulfate (PS) activation for effective treatment of water containment was meaningful and important. Cuprous oxide (Cu2O) was an abundant, cheap metal-oxide material, has attracted much attention for various fields. In this work, the Cu2O was used to activate PS via the oxidative disproportionation process of electron migration. Meanwhile, the redox disproportionation process would affect the PS activation. To overcome this troublesome. Here, a Schottky junction of Ag/Cu2O composite was designed to affect electronic transmission by in-situ decorated process with biomass materials in mild condition. The Ag/Cu2O/PS exhibited highly efficient activity for tetracycline (TC) degradation by PS activation, the 95% of TC was removed within 30 min, which was 1.84 times higher than Cu2O/PS system. Besides, the response surface methodology (RSM) was used to determine the relationship of pH values, TC concentration and PS dosage for TC degradation. The optimal pH value, TC concentration and PS dosage was selected as 7.0, 30 mg/L and 300 mg/L, respectively. The trapping experiments demonstrated the ‧OH and SO4.− radicals took part in the degradation process and the relative contribution of each radial was calculated. This work would provide new insight to develop efficiency by PS activation. [ABSTRACT FROM AUTHOR]

CuO/Cu2O/Cu ternary composites were prepared using a Cu metal-organic framework (MOF) and melamine as raw materials using a simple calcination process. The ultraviolet and visible light catalytic properties of the CuO/Cu2O/Cu composites were evaluated through methylene blue (MB) degradation. Results show that a ternary CuO/Cu2O/Cu composite was obtained when a single Cu-MOF was calcined in air. The Cu and Cu2O in the product decreased as the melamine in the raw material increased. CuO/Cu2O/Cu composites have excellent photocatalytic properties with the aid of H2O2. When the melamine in the raw material was 15%, the photocatalytic performance of the composite material was the best. With the aid of H2O2, MB was almost completely degraded under ultraviolet and visible light irradiation for 3 and 20 min, respectively. [ABSTRACT FROM AUTHOR]

In this study, Cu2O particles was synthesis by using chemical reduction method. The XRD, FTIR, SEM and UV-Visible spectroscopy were utilised to characterise the synthesised Cu2O particles. The observed data matches previously reported XRD data of Cu2O particles (JCPDS File number 01-075-1531), confirming the fabrication of pure phase particles. The crystallite size of the synthesised Cu2O particles is 39.91 nm was calculating by using Scherrer formula. The band gap of synthesised Cu2O was measured at 1.91 eV using UV-Vis. Morphology and topography were identified using SEM investigation, illustrating development. FTIR analysis confirmed the functional group of particles. The experimental variables related to Cu2O particles photocatalytic methylene blue (MB) dye degradation. The measured MB degradation efficiency was 58.27%, at 10 ppm dye concentration, 60 min reaction duration, and 10 mg catalyst dosage. Effective adsorption and photocatalytic elimination of typical organic pollutants (MB) were proven by the Blue LED. The understanding of Cu2O-based photocatalyst design for organic pollutants degradation. [ABSTRACT FROM AUTHOR]

Photovoltaics is the third-largest renewable energy source in the world today due to its popularity; however, thin-film solar cells are currently replacing PV due to material limitations in large-scale applications. These cells must be developed from widely accessible, fairly cost-effective, and environmentally benign materials. Silica nanoparticles derived from rice husk (SiO2np) and doped Cu2O thin films were examined for solar cell applications. A nebulizer spray technique was used to deposit SiO2np of 0.25, 0.5, 0.75, 1, and 1.25 wt% onto Cu2O. The electrical, optical, and microstructural properties of the deposited thin films were studied. The presence of SiO2np in the Cu2O phase was observed in the XRD spectrum. The structural, optical, and electrical properties of SiO2np: Cu2O thin films were highly affected by SiO2np doping. The energy bandgap and optical transmittance are reduced with a rise in SiO2np doping. An 84.61% and 98.85% increment in mobility and carrier concentration and a 33.87% and 72.72% decrease in band gap and resistivity were obtained at 1.25 w% SiO2np:Cu2O. It was established that SiO2np:Cu2O thin films produced 0.480% power conversion efficiency and 0.30 V open-circuit voltage. [ABSTRACT FROM AUTHOR]

Polymeric films composed of polyvinyl alcohol (PVA) with different percents of CeO2 and Cu2O were prepared using casting method to form PVA/(x) Cu2O (15-x) CeO2 composite at doping concentrations of (0, 1, 5, 7.5, 10, and 15 wt%). The addition of CeO2 and Cu2O affect the structural, morphological, vibrational, and optical properties of PVA film. The lattice parameters of the films were measured. PCC7 film with 15% Cu2O and 0% CeO2 in PVA polymer-matrix, is a suitable candidate to be utilized in UV-shielding for solar cell applications, because of its capability of blocking UV between 190 and 230 nm. The optical energy gap of films varies between 4.77 and 3.32 eV for the indirect transitions and between 4.84 and 3.83 eV for the direct transitions, hence the PCC5 with 7.5% Cu2O and 7.5% CeO2 has the lowest values of direct and indirect energy gaps, which attributed to the enhancement of electronic transitions correlated to the equal ratio of p type Cu2O and n type CeO2 doping. The average value of the refractive index nav was measured according to different approaches. Also, the nonlinear refractive index n2 was measured, it was found that PCC5 has the largest value of nav and n2. [ABSTRACT FROM AUTHOR]

The optical properties of Cu2O nanowhiskers grown by the liquid method with material deposition in an electric field have been studied. The spectral lines forbidden by the selection rules for perfect Cu2O crystals were found in the Raman spectra. The nature of related phonon states is analyzed. In the photoluminescence spectra in the red and near-IR regions, broad bands of defective origin are observed. It was found that the presence of a band at 650 nm (1.9 eV) is a specific feature of the photoluminescence of nanowhiskers. Its properties are studied and possible radiation mechanisms are discussed. In the intrinsic absorption region of nanowhiskers, the photoluminescence band at 572 nm (2.17 eV) associated with band-band transitions is detected. At a low excitation level, the emission of a free exciton n = 1 of the yellow exciton series is observed with simultaneous emission of an optical phonon. [ABSTRACT FROM AUTHOR]

A self-powered photodetector based on copper oxide thin film (Cu2O-TF) is deposited using the e-beam evaporation technique. One notable advantage of this fabrication process is that it does not require the use of any catalysts. The XRD analysis revealed the presence of cuprous oxide (Cu2O) with a distinct peak at ~ 42.66º indicating (200) orientation. SEM analysis confirms the successful growth of the Cu2O-TF, revealing a porous semi-spherical structure with a measured thickness of ~ 100 nm. Moreover, electrical analysis was studied for the voltage range of − 2 to 2 V. The Cu2O-TF device exhibited a rectification ratio (RR) of 64 at + 1 V. Notably, the device exhibited self-powered characteristics, showing a stable switching response characterized by rise time (τr) values of ~ 0.183 sec and fall time (τf) of ~ 0.236 s at 0 V. Furthermore, the device obtained maximum responsivity in the near IR region, extending from ~ 700 to 800 nm, with peak intensity reaching ~ 720 nm along with responsivity values of ~ 6.6 mA/W. Moreover, the device obtained a detectivity value of ~ 3.45 × 1011 Jones and a low-noise equivalent power of ~ 8.12 × 10–12 at 0 V. The overall results highlight the suitability of the device for self-powered photodetector applications. [ABSTRACT FROM AUTHOR]

Antimony (Sb) chalcogenides, particularly antimony selenide (Sb2Se3), have gained attention as promising semiconductor materials in order to creat and advancement of competitive solar cells. These materials exhibit a range of desirable qualities, such as excellent absorption rate, ability to modify band gap, and plentiful in the crust of the earth. This article describes an antimony selenide (Sb2Se3) absorber based high-efficient thin film solar cell (TFSC) with copper oxide (Cu2O) as as back surface field (BSF) by dint of Al/ITO/TiO2/Sb2Se3/Cu2O/Ni heterostructure using SCAPS-1D Simulator. This research entails an in-depth assessment of various physical and electrical characteristics of every solar active semiconductorof TiO2,Sb2Se3, and Cu2O covering the thickness of each layer, concentration of carrier doping, defect density in the bulk and at the interface, carrier generation rate together with recombination. Initially, the variation in photovoltaic parameters of open circuit voltage (Voc), short-circuit current density (Jsc), fill factor (FF), power conversion efficiency (PCE), and quantum efficiency (QE) investigated without the BSF layer, followed by a comprehensive analysis on the role of Cu2O BSF layer for enhancing cell's performance explored systematically. The proposed heterostructure shows improved PCE of over 32% (which was 21% without BSF) with JSC of 37.492 mA/cm2, VOC of 1.024 V, and FF of 83.595%. Thus, the utilisation of a heterostructure comprising Sb2Se3 absorber and copper oxide Cu2O BSF layer demonstrates significant promise in the development and production the high-efficiency greenery thin-film solar cells (TFSCs). [ABSTRACT FROM AUTHOR]

Fe3O4 and Cu2O were successively immobilized on alkali-treated straw, and the magnetically separable straw@Fe3O4/Cu2O composite was obtained. The straw@Fe3O4/Cu2O was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometry, respectively. Photocatalytic performance of the straw@Fe3O4/Cu2O was evaluated by measuring the degradation of methyl orange (MO) under irradiation of visible light. The introduction of Fe3O4 not only endowed the straw@Fe3O4/Cu2O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs. The active species capture experiment showed that holes (h+), hydroxyl (·OH) and superoxide (·O2−) radicals all took part in the MO degradation. In addition, the photocatalytic mechanism of straw@Fe3O4/Cu2O was proposed based on the experimental results. After five cycles for the photodegradation of MO, the straw@Fe3O4/Cu2O still displayed good photocatalytic activity, suggesting that the as-prepared composite had great potential for practical use in wastewater treatment. [ABSTRACT FROM AUTHOR]

New Cu2O@TiO2 core-shell microspheres were successfully prepared for the first time in this paper. The XRD, N2 adsorption-desorption, SEM, TEM, EDX and XPS characterizations were utilized to investigate the physical and chemical properties. The liquid phase oxidation of naphthalene was also carried out to test their catalytic performance. The characterization results indicating that the Cu2O microspheres were firstly formed by hydrothermal treatment and the rutile TiO2 coating on the surface would be formed by the hydrolysis of tetrabutyl titanate. The Cu2O@TiO2-5.0 catalyst with the molar ratio of copper to titanium species as high as 5.0 has the largest surface area and maximum pore volume resulting from the integrated microspheres with rougher surface thickness of about 6.3 nm, and it showed higher catalytic performance in the liquid phase oxidation of naphthalene. Naphthalene conversion of 43.2%, 1, 4-naphthoquinone selectivity of 26.7% and phthalic anhydride selectivity of 53.4% can be obtained, and it only slightly decreased even after repeated use for 5 times. The method would provide a valuable theoretic reference for the hindrance of Cu2O rapid deactivation and the industrial application of the naphthalene oxidation to produce high valuable chemicals. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the formation of Cu2O thin films on fluorine-doped tin oxide glass substrate by electrochemical deposition. The obtained Cu2O thin films were annealed in air at various temperatures from 300 to 500°C. X-ray diffraction analysis shows that as-deposited and annealed thin films at 300°C have a cubic structure with a Cu2O composition. The Cu2O films annealed at 400 and 500°C were completely converted onto the monoclinic structure with CuO composition. On the other hand, atomic force microscope and scanning electron microscope images showed that the shape of Cu2O grains was changed significantly from cubic to grains upon annealing. Mott–Schottky and photoelectrochemical measurements indicate that Cu2O thin films exhibit p-type conductivity before and after annealing. Photoluminescence measurements indicated two peaks at around 523 and 355 nm, which confirmed the existence of Cu2O and CuO thin films, respectively. Finally, the CuO nanostructures obtained at 500°C exhibited a high photocurrent enhancement and stability compared to as-deposited sample. As a consequence, the optical bandgap was reduced from 2.41 to 1.75 eV. [ABSTRACT FROM AUTHOR]

The effect of the energy, the interval between the pulses, and the number of double laser pulses on the formation of the component and charge composition of laser plasma by laser spark spectrometry (LSS-1 spectrometer) was studied. The processes leading to the formation of mixed nanopowders of copper and aluminum oxides, precursors for the production of nanoceramics and films of CuAlO2 copper aluminates by the action of double laser pulses on a hybrid target consisting of cemented aluminum and copper plates, from AD1 and M2 alloys were investigated. It was shown that precursors for the manufacture of nanoceramics and nanofilms of CuAlO2 copper aluminates can be obtained by the successive action of a series of double laser pulses with energy of 53 mJ and an interval of 10 μs on a hybrid target. A closed glass weighing bottle containing the target was used for the products formed during interaction of the aluminum and copper ions with atmospheric oxygen. The size of the initial particles, determined by means of a high-resolution electron microscope, amounted to 30–45 nm. The particles were assembled into agglomerates and had a crystalline structure and spherical form. On account of the purely diffusion transfer mechanism of the fractals the size and amount of the fractal aggregates settling on the support situated at the bottom of the cuvette were several times greater than the amount of the products that settle on the side support. The main contribution to change in the intensity of the spectral lines for the Al and Cu atoms and ions and the AlO molecular bands comes from interaction of the second pulse with the condensation products formed in the channel after the action of the first pulse. With increase in the number of long-lived fractal aggregates in the air the intensity of molecular bands and lines decreases by ~1.5 times for Al III and by ~2 times for copper, which is due to active interaction of the long-lived large fractals that accumulate in the air with the incident radiation. [ABSTRACT FROM AUTHOR]

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Cuprous oxide (Cu2O) is a promising photocathode for photo-electrochemical hydrogen production. One of the main issues limiting the application of Cu2O is photo-corrosion in aqueous electrolyte during the PEC process. Herein, to improve the stability of Cu2O, for the first time, a soluble polymer polyimide (PI) was introduced as a protective layer using a facile spin-coating method. It was found that dense PI films effectively isolated Cu2O from the aqueous electrolyte and inhibited self-reduction and oxidation reactions of Cu2O as evidenced by XRD spectra. Compared with bare Cu2O, the photocurrent density and stability of modified Cu2O samples were increased with increasing the spin-coating amount of PI solutions. It was found that sample Cu2O/PI-200 showed the highest current density value of 1.8 mA/cm2 at 0 VRHE after 1200 s without attenuation, which is 40 times higher than the bare Cu2O (0.04 mA/cm2 at 0 VRHE). Further enhancing the PI amount, such as sample Cu2O/PI-300, will lead to a very stable but lower current density (1.48 mA/cm2) during the whole test duration. EIS measurements indicated that thicker PI films lead to larger charge transfer resistance and higher capacitance in the space charge layer. Therefore, there is an optimum amount of PI (Cu2O/PI-200) to balance the above two opposite effects and achieve the best PEC performance. This work provides a facile strategy to improve the PEC activity and stability of Cu2O, which may be extended to other systems with photo-corrosion problems, such as BiVO4 or ZnO. [ABSTRACT FROM AUTHOR]

The importance of Cu2O nanoparticles (NPs) is growing day to day because of their unique properties. For the possible application of these NPs in optoelectronics, it is desirable to synthesise the size-controlled Cu2O NPs and understand their microstructural, optical, and electronic properties. Here, we report the synthesis of Cu2O particles having nano-crystallites of average sizes in the range of about 8–10 nm using glycerol and copper acetate monohydrate by the microwave synthesis method for varying microwave power. The band gaps of the nano-crystallites have been obtained from the optical absorption studies and are found to be 2.14 eV, 2.12 eV and 2.08 eV for microwave powers of 180 W, 360 W, and 540 W, respectively. The increase of bandgap with a decrease in particle size is mainly due to the quantum confinement effects in small Cu2O particles. Blue and green photoluminescence (PL) emissions have been observed, and the intensity of these is seen to change for different microwave powers. The changes in PL intensities are argued due to the change in the microstructural properties of the nano-crystallite Cu2O particles. Detailed systematic analysis of the X-ray diffraction data employing the Williamson–Hall method clearly indicates that there are significant changes in microstructural parameters viz, strain, stress, and the deformation of energy density in the Cu2O nano-crystallites synthesised for different microwave powers. The observed changes in the microstructural parameters were induced due to the microwaves produced for varied powers. Also, the formation of Cu2O particles has been confirmed through Raman spectroscopy and X-ray Photoelectron Spectroscopy studies. [ABSTRACT FROM AUTHOR]

Fiber optic surface plasmon resonance sensors based on bi-layers of Ag–TiO2 and Ag–Cu2O are proposed and analyzed experimentally. Influence of oxide layer thickness on the sensitivity of sensors has been discussed. Sensor based on Ag–Cu2O bi-layers has been found to be more sensitive than that of Ag–TiO2 bi-layers. Also, 40 nm Ag-5 nm Cu2O bi-layers based sensor acquires highest sensitivity. Its sensitivity diminishes with rise in thickness of Cu2O layer beyond 5 nm. [ABSTRACT FROM AUTHOR]

Effect of citric acid (φ = 0.5–1.3) and glycine (φ = 0.5; 0.7–0.9) ratio on the rate of combustion reactions, phase composition, and particle size of CuOx powder obtained from copper nitrate solution under conditions of open and closed reactors has been considered. Modeling of combustion reactions for the synthesis of CuOx has shown that calculations of Tmax by equation derived for synthesis in combustion reactions are possible also for thermolysis or pyrolysis reactions. Formation, morphology, and dispersity of samples after completion of combustion reactions and thermal treatment at 500°C have been studied by X-ray diffraction and electron microscopy. The characteristics of combustion profiles display transition from bulk combustion mode to self-propagating high-temperature synthesis and further to thermolysis of xerogels when citric acid content increases. It has been found that retardation of redox reaction rate does not decrease CuO loss due to removal of copper within organic volatile components. [ABSTRACT FROM AUTHOR]

Cu2O as a new heterogeneous green nanocatalyst is biosynthesized from Cressa leaf extract and characterized by some techniques including XRD, FTIR, UV–Vis, SEM, and TEM. Then, the prepared nanocatalyst was applied in the synthesis of some chromeno[4,3-b]chromenes under aerobic conditions. Reusability studies warrant acceptable reproducibility of the nanomaterial. Low reaction time, easy workup, cost-effectiveness, wide substrate scope, good to excellent yield, and complete atom economy are significant features of this new method. At the final part of this study, the in vitro cellular toxicity of Cu2O nanoparticles is examined on SKOV3 human ovarian carcinoma cell line via an MTT assay. The reduction in cell viability proved the cytotoxicity of the nanoparticles toward the performed ovarian cancer cell line. [ABSTRACT FROM AUTHOR]

For the first time, cotton fiber-shaped Cu2O nanoparticles were prepared onto the surface of a commercial copper (Cu) foil via a very simple immersion method at room temperature in which the soaking solution only contained CuSO4, Na2S2O3, and a very little amount of 1-butyl-3-methylimidazolium trifluoroacetate. In this work, the current collectors prepared using 1 mM, 2 mM, and 3 mM Na2S2O3 were, respectively, nominated as current collectors a, b, and c. Interestingly, a cotton fiber-shaped spatial network structure assembled by a large number of 10-nm-sized nanoparticles was presented on the surface of current collector b. The initial discharge capacity (DC) at 0.1 A g−1 of electrode b, namely, the graphite electrode assembled using current collector b, was as high as 467 mAh g−1, almost 1.65 times larger than that of the conventional graphite electrode. Particularly, at 0.5 A g−1 after 10 cycles, the DC value of electrode b (105 mAh g−1) was still about 1.8 times higher than that of the conventional graphite electrode (59 mAh g−1). An immersion method for preparing Cu2O-modified Cu foil at room temperature is developed in this work, which is very meaningful to the development of the Cu foil-based commercial graphite electrode, since no additional energy consumptions and no variations of the electrode preparation process are required. [ABSTRACT FROM AUTHOR]

In this work, n+-PSi/p-CuO/n-Cu2O bilayered heterostructure has been fabricated and tested against CO2 gas. p-type cupric oxide CuO was fabricated by a two-step thermal evaporation/oxidation process of copper (Cu) thin films. Subsequently, the n-type cuprous oxide Cu2O was deposited by electrochemical method on the top of the CuO/porous silicon (PSi) structure in an aqueous acetate bath [copper acetate (C4H6CuO4) and sodium acetate (C2H3NaO2)]. The current–voltage (I–V) and response time (I–t) characteristics of the heterostructure device to CO2 gas environment were studied. We have demonstrated that the bilayered PSi/CuO/Cu2O structure is sensitive to CO2 gas with a high sensitivity of the order of 80% at low bias potential (0.85 V) and fast response time of the order of 1 s at room temperature. Finally, a CO2 gas sensing mechanism has been proposed. [ABSTRACT FROM AUTHOR]

Cuprous oxide (Cu2O) is a highly efficient p-type semiconductor, which has an appropriate band gap and favorable energy band positions, making it ideal to be considered as a photocathode material for photoelectrochemical (PEC) water splitting. However, the theoretical efficiency of Cu2O is still unachievable in practical situations due to the low separation rate of photogenerated electron–hole pairs. In this work, the surface of the Cu2O film was directly converted to CuO by thermal oxidation to form a Cu2O/CuO heterojunction with fewer defects at the interface. The PEC tests suggest that the Cu2O/CuO photocathode exhibits a photocurrent density of − 1.99 mA/cm2 at 0 V vs. RHE benefit by the heterojunction with a good interface for efficient charge separation and transfer, which is 3.3 times higher than Cu2O (− 0.6 mA/cm2). Furthermore, the performance of Cu2O/CuO can be greatly enhanced by depositing a Pt co-catalyst layer. The photocurrent density of Cu2O/CuO/Pt composites was 4.6 times higher than pristine Cu2O. More exciting, the stability of Cu2O with the CuO and Pt co-catalyst only presents a decline of 20% under illumination for 3600 s. This work points to the effective means of thermal oxidation that can form a heterojunction with relatively fewer interface defects and provides a strategy for the performance improvement of Cu2O photocathode in PEC water reduction. [ABSTRACT FROM AUTHOR]

Herein, we report a chemoselective insertion of CO2 into unsaturated alkyne substrates under ambient conditions, which is achieved over poly (sulfobetain methacrylate) (p(SBMA)) supported Cu2O nanocatalyst (Cu2O/p(SBMA)) and a series of 3a,4-dihydronaphtho[2,3-c]furan-1(3H)-ones, can be obtained in excellent yields. Cu2O/p(SBMA) presents high performance for environment pressure activation and interpolation of CO2 into unsaturated alkyne substrates. This provides an attainable and competent catalyst for interpolation of CO2 into aryl alkynes, and binding allylic chlorides through SN2 mechanism in order to produce efficient ester and lactone heterocycles that are supposed to have favorable utilizations. All in all, these findings signify practical methods of hybrid catalyst development for detailed alterations, including CO2 employment in a green and sustainable manner. [ABSTRACT FROM AUTHOR]

In this work, the effect of the applied cathodic potential on properties of electrodeposited p-type Cu2O thin films was investigated. Electrochemical deposition was carried out on indium tin oxide (ITO) substrate from alkaline Cu(II) lactate-based solution at different cathodic potentials (− 0.60 to − 0.80 V vs. Ag/AgCl) without subsequent annealing. It was shown that changing the electrodeposition applied potential could tune both the phase structure and band gap energy of the Cu2O thin films. The morphological, optical, and structural characterizations of the deposits were carried out using field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and UV-VIS spectroscopy, respectively. FESEM observations of the as-prepared deposits revealed uniform, rough and desert rose-like crystallites composed of square or triangular pyramidal and truncated polyhedral morphologies. The XRD investigation showed that the films were crystalline and revealed the presence of two other sub-stoichiometric copper oxide phases (Cu4O3 and Cu64O), depending on the applied potential. The crystallite size, evaluated using the Scherer formula, varied tightly with the cathode potential and increased in the − 0.65 to − 0.75 V potential range, indicating that the films are of better crystallization. The optical band gaps, deduced from experimental Tauc plots, were found to be 2.33, 1.98, 2.25, 2.27 and 2.50 eV for thin films deposited at − 0.60, − 0.65, − 0.70, − 0.75 and − 0.8 V vs Ag/AgCl, respectively. A mechanism of the phase formation is proposed and discussed. [ABSTRACT FROM AUTHOR]

The evolution and advancement of novel solar power technologies is considered to be a promising solution towards fulfilling the worldwide demand for energy and electricity. The ability to tune the bandgap by varying the size of the atom has made quantum dot solar cell a potential third generations solar cell device. Quantum dot solar cell has many advantages over other traditional solar cells such as low cost, high efficiency, miniaturization etc. Still the performance of quantum dot solar cells (QDSCs) falls behind due to the carrier recombination within the Quasi-neutral region (QNR). The ETL and HTL are the two-layer that highly impacts the performance of the quantum dot solar cell. Therefore, in this work, performance evaluation of PbS-EDT and Cu2O hole transport layer (HTL) is done, achieving a power conversion efficiency (PCE) equal to 15.93 %. The absorber layer used here is treated with tetrabutylammonium iodide (PbS-TBAI) and the electron transport layer (ETL) is TiO2. In the initial section of the work, device optimization is done, followed by an in-depth analysis on the doping densities of the ETL and HTL, then a resistance analysis is also presented to show the effect of resistance on the device, and at the end, a solar cell device is finalized with a doping density of 5 × 10 17 cm - 3 for both (ETL and HTL) with the resistance value to be 1 Ohm.cm2 for series and 106 Ohm.cm2 for a shunt. All the work has been performed using the SCAPS-1D simulator. [ABSTRACT FROM AUTHOR]

By investigating photoelectrochemical (PEC) performance of p and n-type Cu2O, we do an exploratory study on dual-photoelectrode tandem PEC cell consisting of p-Cu2O/Pt photocathode and n-Cu2O/Co–Pi photoanode for the first time. Benefiting from electron capture (Pt) and hole transfer (Co–Pi) layers, the photoelectrodes have better charge separation efficiency and faster charge transfer kinetics. The p-Cu2O/Pt||n-Cu2O/Co–Pi PEC cell finally achieves an unassisted photocurrent density of 0.09 mA/cm2 after illumination for 1000 s, which preliminarily confirms the viewpoint of unassisted overall water splitting. We then anticipate this work can provide a novel platform for the design and fabrication of various PEC energy conversion devices with excellent performance. [ABSTRACT FROM AUTHOR]

Cu2O-based composites had a promising potential for various applications including photocatalysts, solar cells, carbon monoxide oxidation, sensors, and so on. Here, a series of novel visible-light-driven palygorskite (PAL)/Cu2O heterostructures were fabricated via facile deposition-precipitation and reduction methods. The relevant characterization analysis demonstrated that the content of palygorskite played a vital role on the morphologies and optical absorption properties of composites. Compared with pristine Cu2O, the photocatalytic performance and stability of as-prepared PAL/Cu2O composites were obviously enhanced for MO degradation under visible light irradiation, which was mainly ascribed to the construction of heterostructures. It was shown that the tight interface contacts between two components effectively accelerated the transfer and separation of photogenerated holes and electrons. This work may provide some insights into various technological applications of palygorskite for effective light utilization. [ABSTRACT FROM AUTHOR]

In this contribution, we report the screening of different parameters contributing to the electrodeposition of Cu2O nanostructures as an electrode material to provide an overall understanding of the effect of the entire method conditions. We varied different parameters (pH, potential, and deposition time) during the electrodeposition of cuprous oxide (Cu2O) thin films on ITO glass substrate and integrated different methods: X-ray diffraction (XRD), UV-vis absorption (UV-Vis), scanning electron microscope (SEM), cyclic voltammetry (CV), and chronoamperometry (CA) to deeply examine the as-synthesized materials and interrogate their efficiency towards the conversion of light to current (photo-current). From the chronoamperometry experiments, all the curves of current transients exhibit a typical response of a progressive 3D nucleation growth. Highly crystalline Cu2O structures of nano-cubes can be seen in the XRD and SEM results at high pH (12.5) and at potentials -0.5 and -0.6 V Vs. SCE during 60 min of deposition time. UV-Vis results showed high optical absorption in the region of 300-500 nm. The photocurrent measurements of Cu2O coupled with Cu-doped ZnO suggested that the synthesized Cu2O proved to be the best candidate as a solar cell. [ABSTRACT FROM AUTHOR]

New composites formed by layered hybrid TiO2(stearic acid) (LHTiO2) and, Cu2O nanoparticles were studied as photocatalysts that extend the response range to light visible for the evolution of hydrogen and the degradation of 4-chlorophenol. The results revealed that LHTiO2/Cu2O exhibited a clearly improved photocatalytic degradation, about 5.6 times faster than pristine TiO2, and hydrogen evolution of about 2.7 times higher than the TiO2 anatase. The enhanced photocatalytic activity can be assigned to the properties of the two-dimensional morphology, in sheets-like arrangement of LHTiO2, benefitting from the high exposure of surface, with more active sites available to improve matching with the surfaces of the Cu2O nanocrystals and significant reduction of migration distances of photogenerated carriers. In the photocatalytic degradation, a mechanism Z-scheme is supported, and in the photocatalytic evolution of hydrogen a mechanism type II band alignment is indicated. Photocatalytic reuse tests showed that stability and catalytic activity of LHTiO2/Cu2O were maintained for three cycles. Photoelectrochemical evaluation were performed through measurements of the photocurrent response and electrochemical impedance. [ABSTRACT FROM AUTHOR]

Cu metal, surrogate for metallic actinide materials, was subject to accelerated aging through thermal treatment. A multiphase oxide-layer (Cu2O, CuO) was detected, varying with temperature (250–400 °C) and aging time (1–3.5 h). Isotope ratio mass spectrometry revealed temperature-dependent isotopic fractionation of O, evidenced by the enrichment of Cu oxide in 16O isotopes with increasing temperature. Isotopic fractionation occurred initially with atmospheric O, and later through exchange with water vapor. Raman spectra contributed insight on phase fraction and local bonding of Cu oxides. O isotopes could serve as a useful tracer for studying oxide layer growth from aging metallic systems. [ABSTRACT FROM AUTHOR]

High-concentration industrial wastewater containing N,N-dimethylacetamide (DMAc) from polymeric membrane manufacturer was degraded in Cu2O NPs/H2O2 Fenton process. In the membrane-assisted Fenton process DMAc removal rate was up to 98% with 120 min which was increased by 23% over the batch reactor. It was found that ·OH quench time was extended by 20 min and the maximum ·OH productivity was notably88.7% higher at 40 min. The degradation reaction rate constant was enhanced by 2.2 times with membrane dispersion (k = 0.0349 min−1). DMAc initial concentration (C0) and H2O2 flux (Jp) had major influence on mass transfer and kinetics, meanwhile, membrane pore size (rp) and length (Lm) also affected the reaction rate. The intensified radical yield, fast mass transfer and nanoparticles high activity all contributed to improve pollutant degradation efficiency. Time-resolved DMAc degradation pathway was analyzed as hydroxylation, demethylation and oxidation leading to the final products of CO2, H2O and NO3− (rather than NH3 from biodegradation). Continuous process was operated in the dual-membrane configuration with in situ reaction and separation. After five cycling tests, DMAc removal was all above 95% for the initial [DMAc]0 = 14,000 mg/L in wastewater and stability of the catalyst and the membrane maintained well. [ABSTRACT FROM AUTHOR]

The novel nanocomposite Cu2O/MoS2-12 was synthesized by a simple two-step method. Cu2O nanospheres grow on the surface of MoS2 nanoflowers and have high photocatalytic activity. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) X-ray photoelectron spectroscopy (XPS), ultraviolet-visible light (UV-vis) photoluminescence (PL) spectroscopy, UV-vis diffuse reflection (UV-DRS), and electrochemical impedance (EIS) were used to study the structure and properties of the samples. The photocatalytic properties of the materials were evaluated by degrading methyl orange (MO) under visible light. The results show that CM-12 can completely degrade MO in 30 min, and the pseudo-first-order kinetic constant of degradation is 8.76 times that of pure Cu2O, which can be attributed to the composite material that can greatly reduce the recombination rate of photogenerated electrons and holes, and it has good stability. After repeated use for 5 times, the degradation rate can still reach 40%. Through experiments and theoretical results, a possible photocatalytic mechanism is proposed. To the best of our knowledge, this work was the first example of combining MoS2 with Cu2O and applying it to photocatalytic degradation of organic pollutants. It was beneficial for developing new photocatalysts and improving the catalytic performance of conventional photocatalysts. [ABSTRACT FROM AUTHOR]

Radio frequency (RF) magnetron sputtering was used to fabricate Cu-doped Cu2O thin using a gas mixture containing 80% Ar and 20% N2 at room temperature. The Cu2O ceramics containing different concentrations of Cu powder (1–7 wt%) were considered to be the sputtering targets. A highly dense Cu-doped Cu2O target was essential to obtain excellent quality Cu2O films; this target can be obtained via the hot-pressing process because the low melting point (1084.6 °C) of Cu allows enhanced densification of the Cu2O target through a liquid-phase wetting mechanism. X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) were performed to characterize the Cu2O film microstructure. Our results denoted that Cu doping enhances the densification and increases the grain size of the Cu2O films. Further, the crystal structures of the films changed from CuO and Cu4O3 to Cu2O when the Cu doping concentration increased from 1 to 7 wt%. A dense and well-defined columnar morphology can be observed when TEM was used to observe the film microstructure. Subsequently, the electrical and optical properties of the Cu2O thin films were evaluated at different Cu concentrations. The electrical resistivity of the Cu2O films became 8.6 Ω·cm when the Cu doping concentration was 7 wt%, corresponding to a carrier density of 9.8 × 1016 cm−3 and a mobility of 7.5 cm2/Vs. Furthermore, the optical transmission of the Cu2O films doped with Cu was greater than 60%. The band gaps of the films ranged from 2.32 to 2.54 eV depending on the copper oxide phases present in the films. [ABSTRACT FROM AUTHOR]

Cu2O films as photocathodes were synthesized using direct current electrodeposition method. Utilizing a cyclic voltammetry (CV) test before potentiostatic electrodeposition increased the uniformity and transparency of the Cu2O film. The optical band gap of the Cu2O film obtained through electrodeposition for 7200 s was 2.1 eV, while the one electrodeposited for 1000 s showed a blue shift (2.4 eV). The high transparency of the Cu2O film electrodeposited after the CV test and increased thickness of the electrodeposited film for 7200 s did not affect the value of the photocurrent density. The photocurrent density of the electrodeposited films for time periods more than 200 s did not change considerably. The thickness of the Cu2O film electrodeposited for 200 s was measured to be 70 nm. Electrodeposition for above 200 s resulted in Cu2O films with thicknesses greater than the electron collection length, i.e. 20–100 nm, which was the reason why the photocurrent density was not improved. Electrochemical impedance spectroscopy (EIS) was used to explain charge transfer characteristics of the Cu2O photocathode. The Nyquist plot showed two semicircles, which can be attributed to the charge transfer process across the electrode/electrolyte interface and inside the electrode. The EIS data was fitted with an equivalent circuit and the parameters value was derived. Using the Mott–Schottky plot, the flat band potential and the carrier density were obtained to be 0.19 V vs. Ag/AgCl and 1.3 × 1018 cm–3, respectively. [ABSTRACT FROM AUTHOR]

Cuprous oxide (Cu2O) thin films have been successfully electrodeposited onto indium tin oxide-coated glass substrates from copper acetate solution and characterized by x-ray diffraction analysis, scanning electron microscopy, ultraviolet–visible (UV–Vis) spectroscopy, and photoelectrochemical (PEC) and electrical Hall-effect measurements. The effect of the solution pH on the structural, morphological, optical, PEC, and electrical properties of the deposited Cu2O thin films was investigated. The x-ray diffraction results indicated that the prepared Cu2O films exhibited good crystallinity with pure cubic structure, while the crystallite size increased with increasing solution pH. The preferential orientation of the deposited films also changed with the pH value. When the solution pH was changed, the surface morphology changed from spherical to pyramidal shape with increasing grain size. The optical characteristics of the Cu2O thin films were not significantly affected by changing the solution pH value. PEC measurements revealed that Cu2O thin films prepared at pH 6.2 exhibited n-type conductivity, while those obtained at pH 11 showed p-type conductivity. These results were confirmed by Hall-effect measurements. The obtained Cu2O thin films would be promising semiconductor materials for use in various applications such as PEC cells and photovoltaic solar cells. [ABSTRACT FROM AUTHOR]

A Cu2O/Cu columnar array electrode that integrates the active materials and current collector was fabricated through in situ thermal oxidation of the chemically dealloyed Cu–Fe film prepared by co-electrodeposition using copper sulfate and ferric sulfate as raw materials. The effects of the ratio of copper ion to iron ion; the valence of iron ion; and the thermal oxidation temperature on the morphology, structure, and electrochemical properties of the electrode were investigated. Results show that the columnar array electrode not only has a large specific surface area but also has good conductivity, which can effectively improve the utilization of the active material and endow the electrode with an excellent capacitance performance. The prepared electrodes make a reversible redox reaction corresponding to the transformation between Cu2O and Cu within the potential window from − 1 to − 0.2 V in 1 M KOH aqueous solution. The areal capacitance of the optimal electrode is found to be as high as 128.6 mF/cm2 at a scan rate of 5 mV/s, and it shows a capacitance retention of 83.8% after being subjected 5000 charge-discharge cycles at a current density of 9 mA/cm2, indicating good electrochemical stability. [ABSTRACT FROM AUTHOR]

CuO–Cu2O complex thin films were synthesised on glass and p-type Si substrates through the dip-coating method. A precursor solution was prepared by dissolving CuCl2·6H2O powder in methanol. The films were deposited through the dip-coating method and dried at 430 K. One group of samples was irradiated with a green laser (λ = 540 nm, 10 W), and another group of samples was annealed at 530 K or 630 K. Fourier-transform infrared spectroscopy confirmed the presence of the functional groups of CuO and Cu2O. X-ray diffraction and ultraviolet–visible spectroscopy were used to investigate the structural and optical properties of the films. The effects of laser irradiation and annealing temperature on the films were discussed. Results indicated that the deposited CuO–Cu2O complex films were resistive, and Au enabled Ohmic contact. [ABSTRACT FROM AUTHOR]

A novel ITO/NiO/Cu2O structure served as photocathodes was applied in photoelectrochemical (PEC) water splitting for the first time. The NiO integration is found to slightly ameliorate the crystalline structure of Cu2O. PEC measurements showed that NiO-modified Cu2O photocathodes can deliver a higher PEC performance, as the photocurrent density was up to − 1.68 mA/cm2 at − 0.6 V versus RHE under simulated AM 1.5G illumination, which is 2.8 times higher than that of nude one. The enhanced PEC performance may come from the improved charge separation and migration properties of NiO modification. [ABSTRACT FROM AUTHOR]

Propylene epoxidation by oxygen over Cu-based catalysts is a most ideal and economical process. The unsupported CuOx nanoparticles were synthesized by liquid phase reduction method. The crystalline phase and size of CuOx nanoparticles were characterized by XRD and TEM, respectively. The catalytic performances of CuOx with different pretreatment temperatures and atmospheres were also investigated. The as prepared unsupported CuOx nanoparticles were composed of Cu and Cu2O. With elevating the pretreatment temperatures under N2 atmosphere, the size of CuOx nanoparticles increased gradually from 25 nm to 58 nm. However, the relative content between Cu and Cu2O remained almost unchanged, indicating that the valence state of Cu species in CuOx was kept nearly constant. The C3H6 epoxidation activities showed a first increases and then decreases trend with enhancing the particle size of CuOx. The highest activity of propylene epoxidation was achieved when the particle size of CuOx was 41 nm. The conversion of propylene was 0.14% and the selectivity of propylene oxide was 30% respectively under the reaction temperature of 150 °C. The results indicated that the appropriate CuOx particle size was a key factor for propylene oxide formation on Cu-based catalysts. The C3H6 epoxidation activities showed a first increases and then decreases trend with enhancing the particle size of CuOx. When the CuOx particle size was 41 nm, the formation rate of PO reached maximum. The appropriate particle size of Cu species with low valence state was crucial to the generation of PO for C3H6 epoxidation reaction by O2 on Cu-based catalysts. [ABSTRACT FROM AUTHOR]

Nanostructured CuWO4/Cu2O thin films have been developed and used as photocathodes in photoelectrochemical water splitting. Bare Cu2O and CuWO4/Cu2O have been prepared by wet chemical oxidation method. The photocurrent density and photostability of CuWO4/Cu2O significantly increased in comparison with bare Cu2O, according to the results. The photocurrent density values of bare Cu2O and optimized CuWO4/Cu2O samples were 0.8 and 1.8 mA/cm2 (at − 0.6 V vs. Ag/AgCl), respectively. In addition, the remaining photocurrent of optimized CuWO4/Cu2O photocathode was 72% following 1000 s chronoamperometry test, which was over five times greater than that of bare Cu2O photocathode (12.5%). Field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, ultraviolet visible (UV–Vis), Fourier transform infrared and Raman spectroscopy were used to characterize the films prepared. As the results indicate, micro-/nanostructures of various morphologies are formed on the copper plate surfaces. [ABSTRACT FROM AUTHOR]

A tandem photoelectrochemical (PEC) cell consisting of a Cu2O/Ni(OH)2 photocathode and a ZnO/Au photoanode was investigated for unassisted solar water splitting. It was found that the two photoelectrodes were optically matched in UV and visible range, according to the absorbed luminous flux. Compared with the bare Cu2O photocathode, the Cu2O/Ni(OH)2 photocathode had larger photocurrent and smaller onset potential, because the Ni(OH)2 electrocatalysts reduced charge recombination and the overpotential for hydrogen evolution. The tandem PEC cell achieved a photoconversion efficiency of about 0.20% under 1 sun illumination. The results indicate that metal oxide semiconductors synthesized via facile and scalable solution methods are promising photoelectrode materials for unassisted solar water splitting. [ABSTRACT FROM AUTHOR]

Cu2O-n thin films were successfully electrodeposited from a Cu(II) lactate solution containing different concentrations of copper(II) sulfate (CuSO4) and 1 M lactic acid (C3H6O3) at pH 6.5. The electrochemical behaviour of Cu2O thin films has been investigated by means of cyclic voltammetry (CV), chronoamperometry (CA). The nucleation behaviour of the deposited Cu2O has been studied on FTO substrates as a function of Cu2+ concentration. It was found that the nucleation changes from progressive to instantaneous with increasing Cu2+ concentration. Many electrochemical parameters were investigated such as transfer coefficient, diffusion coefficient, cathodic and anodic charges, nucleation rate etc. The effect of the nucleation mechanism on microstructural and optical properties of Cu2O were investigated by X-ray diffractometry (XRD) and ultraviolet visible spectrophotometry (UV–Vis–NIR) and photoluminescence (PL). The optimal concentration of Cu2+ ions was found to be 0.075 and 0.1 M obtained with instantaneous nucleation process. The high photoluminescence (PL) efficiency observed indicating good optical properties with a high carrier density, small depletion layer, high photo-generated electron–hole pairs, narrow band gap and low charge transfer resistance. This results exhibit a high photoelectric performance. [ABSTRACT FROM AUTHOR]

Cabbage-type morphology of cupric oxide (CuO) and cuprous oxide (Cu2O) nanostructures were synthesized via a simple and cost-effective chemical approach. HRTEM, FESEM, XRD, UV–Vis absorption and photoluminescence spectroscopies were used to identify the structural, optical, morphological and catalytic properties of the prepared nanostructures. Phase of the prepared copper oxide nanostructures was well controlled by changing the concentration of glucose. The prepared cabbage-type Cu2O nanostructures showed exceptionally improved catalytic performance towards the reduction of toxic 4-nitrophenol into useful 4-aminophenol as compared to cabbage-type CuO nanostructures. Cabbage-type Cu2O nanostructures completely transformed 4-NP into 4-AP in just 5 min with excellent rate constant (0.587 min−1). The observed excellent catalytic activity of prepared cabbage-type Cu2O nanostructures indicates their potential use in catalytic applications. [ABSTRACT FROM AUTHOR]